I believe you became a resident as of January 1, 2018. For the F1 visa , you count 5 year OR part years (2013,2014, 2015, 2016, 2017). As a US resident in 2018, you may qualify for the Lifetime Learning Credit. The American Opportunity Credit is only available for the first 4 years of college as an undergraduate.
Please see additional information on the Lifetime Learning Credit and the requirements to claim the credit.
Please also see information from the IRS as to how to count your F1 years of nonresidency.
https://turbotax.intuit.com/tax-tips/college-and-education/what-is-the-lifetime-learning-tax-credit/...
https://www.irs.gov/individuals/international-taxpayers/alien-residency-examples
